Buffer Solutions and Henderson-Hasselbalch Equation

NaHCO3 dissociates into Na+ and HCO3- in solution.

pH = pKa + log10([HCO3-]/[H2CO3]).

0.029 moles of NaCO3- would be present.

<p>PhCO2H ⇌ H+ + PhCO2-.</p> Signup and view all the answers

<p>pH = pKa + log10([PhCO2-]/[PhCO2H]).</p> Signup and view all the answers

<p>The ratio is approximately 7.8:1.</p> Signup and view all the answers

<p>Buffer effectiveness increases with higher concentrations of its components.</p> Signup and view all the answers

<p>The pH is approximately 7.48.</p> Signup and view all the answers

<p>TRIS becomes 0.004 M and TRIS-H+ increases to 0.016 M.</p> Signup and view all the answers

<p>Degree of ionization, extent of solvation, and ion-ion vs. ion-solvent interactions.</p> Signup and view all the answers

<p>It relates the pH of a solution to the pKa of the acid and the ratio of the concentrations of the conjugate base to the acid.</p> Signup and view all the answers

<p>Acetic acid is a weak acid while sodium acetate is its conjugate base; together they resist changes in pH when small amounts of acids or bases are added.</p> Signup and view all the answers

<p>The pH is approximately 4.76, which is equal to the pKa of acetic acid.</p> Signup and view all the answers

<p>The concentration of AcO- decreases to 2.15 × 10−3 mol, while the concentration of AcOH increases to 2.35 × 10−3 mol.</p> Signup and view all the answers

<p>Because the concentration of the added acid is much lower than that of the buffer components, the pH change is minimal.</p> Signup and view all the answers

<p>The buffering effect will break down, leading to a significant decrease in pH.</p> Signup and view all the answers

<p>The pKa of TRIS-H+ is 8.08, making it stable around a pH of 8.0 due to the close relationship between pH and pKa.</p> Signup and view all the answers

<p>NaH2PO4/Na2HPO4 and KH2PO4/K2HPO4, both have a pH range of 6-8.</p> Signup and view all the answers

<p>HEPES is a zwitterionic buffer that is effective in biological systems, with a pH range of 6.8 to 8.2.</p> Signup and view all the answers

<p>The ratio is approximately 1.0:1, as pH and pKa are nearly equal.</p> Signup and view all the answers

<p>The activity of an ion is given by the formula $a_i = \gamma_i [i]$.</p> Signup and view all the answers

<p>The Debye-Hückel limiting law shows that $\log_{10} \gamma^{\pm} = -A z^+ z^- \sqrt{I}$, where $A$ is a constant, $z^+$ and $z^-$ are the charges of the ions, and $I$ is the ionic strength.</p> Signup and view all the answers

<p>The ionic strength, $I$, is calculated as $I = \frac{1}{2}[(0.3M)(1^2) + (0.1M)(3^2)] = 0.60 M$.</p> Signup and view all the answers

<p>The mean activity determines the effective concentration of ions, influencing equilibrium positions in chemical reactions.</p> Signup and view all the answers

<p>The relationship is given by $pKa + pKb = pKw$, showing that the acidity and basicity constants are inversely related.</p> Signup and view all the answers

<p>$I = \frac{1}{2}[(0.1M)(2^2) + (0.05M)(1^2)] = 0.075 M$.</p> Signup and view all the answers

<p>The mean ionic concentration is $[±] = n\sqrt{([+]^n([-])^n)} = 0.228 M$ for Na3PO4.</p> Signup and view all the answers

<p>$\gamma^{±} = 0.066$ based on the calculated activity coefficient for Na3PO4.</p> Signup and view all the answers

<p>Activity quantifies the effective concentration of an ion, accounting for non-ideal behavior in a solution.</p> Signup and view all the answers